首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   19370篇
  免费   824篇
  国内免费   15篇
耳鼻咽喉   293篇
儿科学   781篇
妇产科学   479篇
基础医学   2036篇
口腔科学   305篇
临床医学   1630篇
内科学   4117篇
皮肤病学   204篇
神经病学   2537篇
特种医学   990篇
外科学   3323篇
综合类   75篇
一般理论   4篇
预防医学   892篇
眼科学   802篇
药学   611篇
中国医学   2篇
肿瘤学   1128篇
  2023年   441篇
  2022年   599篇
  2021年   653篇
  2020年   814篇
  2019年   519篇
  2018年   503篇
  2017年   504篇
  2016年   488篇
  2015年   557篇
  2014年   1023篇
  2013年   919篇
  2012年   707篇
  2011年   641篇
  2010年   761篇
  2009年   774篇
  2008年   689篇
  2007年   676篇
  2006年   721篇
  2005年   672篇
  2004年   598篇
  2003年   533篇
  2002年   571篇
  2001年   484篇
  2000年   498篇
  1999年   443篇
  1998年   209篇
  1997年   184篇
  1996年   135篇
  1995年   142篇
  1994年   133篇
  1993年   90篇
  1992年   400篇
  1991年   398篇
  1990年   393篇
  1989年   410篇
  1988年   382篇
  1987年   189篇
  1986年   61篇
  1985年   108篇
  1984年   132篇
  1983年   156篇
  1982年   130篇
  1981年   91篇
  1980年   96篇
  1979年   90篇
  1978年   59篇
  1977年   81篇
  1976年   80篇
  1975年   63篇
  1973年   63篇
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
11.
BackgroundDental caries is the most common chronic childhood disease. Past studies revealed that grandparents provide their grandchildren with cariogenic foods and beverages (eg, those with free sugars and/or modified starches). Qualitative research can help identify what drives this phenomenon.ObjectiveOur aim was to examine mothers’ explanations for why grandparents in north central and central Appalachia give their grandchildren cariogenic foods and beverages.DesignA qualitative study on children’s oral health in Pennsylvania and West Virginia from 2018 through 2020 was performed. In-person, semi-structured interviews were conducted. Qualitative data from interviews were recorded, transcribed, and then coded using NVivo. Data analysis for this study was performed using thematic analysis with iterative theme development.Participants/settingThe participants were 126 mothers of children aged 3-5 years from West Virginia (n = 66) and Pittsburgh, PA (n = 60).Main outcome measuresMothers’ perspectives about why grandparents give their grandchildren cariogenic foods and beverages were analyzed.ResultsIn the study sample, 85% of mothers (n = 107/126) named at least 1 of their children’s grandparents as a member of their social network responsible for their children’s oral health. From these interviews, 85% of mothers (n = 91/107) discussed that grandparents gave their grandchildren cariogenic foods and beverages. The mothers described the following 4 themes to explain why grandparents gave their grandchildren cariogenic foods and beverages: privilege of the grandparent role; responsibilities of the grandparent role; symbol of care and affection; and limited consideration or understanding of the detrimental impact.ConclusionsGrandparents play a role in giving their grandchildren cariogenic foods and beverages, which could potentially contribute to childhood caries. Research is needed to develop effective social interventions to help some grandparents understand the implications of a cariogenic diet on their grandchildren’s oral health and/or decrease their provision of cariogenic foods and beverages.  相似文献   
12.
Study ObjectiveMONOFIX, a new absorbable barbed suture device, has a triangular stopper at the end to hold the suture to the tissue without hooking the looped end or knotting. The aim of this study was to compare the biomechanical strength and histologic features of MONOFIX with other barbed suture devices using a porcine model.DesignWell-designed, controlled trial without randomization.SettingAnimal laboratory in university hospital.SubjectsSixteen, 60-kg, mature female domestic pigs (skin closure group) and 5, 60-kg, mature female domestic pigs (fascial closure group).InterventionsIn the skin closure group, 3-0 MONOFIX versus 2 widely used 3-0 absorbable barbed sutures (3-0 V-Loc 180 or Stratafix). In the fascial closure group, 2-0 MONOFIX versus 1 widely used 2-0 absorbable barbed sutures (2-0 Stratafix).Measurements and Main ResultsIn the skin closure group, the biomechanical wound strength of skin sutured with size 3-0 MONOFIX, V-Loc 180, or Stratafix was evaluated by postoperative day assessment (days 0, 3, 7, 14, and 28). In the fascial closure group, pigs underwent 2 paramedian incisions and were sutured with 2-0 MONOFIX or with 2-0 Stratafix to evaluate histologic reaction. At 6 weeks the tissues around the suture line were excised and microscopically evaluated. The biomechanical strength of the MONOFIX had similar tissue tensile strength compared with the control, regardless of postoperative day. In the fascial closure model, there was no significant difference in the average tissue reaction score between MONOFIX and Stratafix (1.2 ± .3 vs 1.3 ± .3, p = .478).ConclusionThis study demonstrated that MONOFIX has equivalent tensile strength and histologic reaction when compared with commonly used barbed suture devices. Accordingly, this preclinical study suggests that the use of MONOFIX is a safe alternative to other barbed suture devices.  相似文献   
13.
14.
Replantation of the lower leg has controversial indications, but it may be considered in carefully selected patients. Although the function of prosthetic lower legs has been improved in recent decades, leg salvage remains a laudable goal. We present the case of a 7-year-old child who sustained a traumatic amputation at the level of the middle tibia with loss of the middle portion of the lower leg. We performed successful replantation, and tibia lengthening was performed starting 10 days after replantation and lasted 6 months.  相似文献   
15.
16.
17.
18.
19.
《Transplantation proceedings》2019,51(6):2060-2065
ObjectiveTo explore the protective effect and underlying mechanism of allicin (ALC) on myocardial ischemia reperfusion (MI/R) injury in rats.MethodsThe model of MI/R injury in rats was induced by ligating the left anterior descending branch of the coronary artery. Thirty male Sprague-Dawley rats were randomly divided into 3 equal groups (n = 10): sham group, MI/R injury group, and ALC precondition group. Enzyme-linked immunosorbent assay was used to examine the expression of cardiac troponin I, CK-MB, interleukin-6, tumor necrosis factor-α, and interleukin-8 in the rats' serum. Hematoxylin and eosin staining was used to observe the myocardial pathologic morphology. A physiological recorder was used to measure cardiac systolic and diastolic function. Western blot analysis was used for detecting the expression of p38 and p-p38 in myocardium. The content of malondialdehyde and the activity of superoxide dismutase, catalase, and glutathione peroxidase in myocardium were examined by automatic analysis with the thiobarbituric acid chromogenic and dinitrobenzoic acid methods, respectively.ResultsALC can significantly decrease the expression of cardiac troponin I, CK-MB, interleukin-6, tumor necrosis factor-α, and interleukin-8 in the serum and reduce the myocardial pathologic injury and the expression of malondialdehyde and p-p38 in myocardial tissue. Moreover, ALC can upregulate the activity of superoxide dismutase, catalase, and glutathione peroxidase and improve myocardial systolic and diastolic function with no influence on the expression of p38.ConclusionALC can protect rats against MI/R injury by suppressing inflammation and oxidative stress. The mechanism is associated with alleviating the activation of p38 signaling.  相似文献   
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号